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Seed Packet Coverage Calculator

Estimate seeds and whole packets for a square planting grid using spacing and assumed germination.

Number from 1 to 100000 sq ft.
Number from 1 to 120 in.
Number from 1 to 100 %.
Number from 0 to 100 %.
Whole number from 1 to 100000 seeds.

Enter values in the units shown. Empty fields, fractions, comma-formatted numbers, values outside the listed ranges, and non-finite values are rejected.

Planting sites
Seeds to sow
Whole packets

How to use this calculator

  1. Measure the project or enter costs from a current quote or product label.
  2. Adjust the quantities, coverage, package size, and allowances to match your situation.
  3. Select Calculate, then check the method, worked example, and limitations below.

Formula and method

Sites = area × 144 ÷ spacing², rounded up. Seeds = sites ÷ germination rate × (1 + extras%), rounded up. Packets round up.

Whole packages and pieces are rounded up. Results disappear when an input changes until the new values are calculated.

Worked example

Planting area 100 sq ft; Spacing 12 in; Expected germination 80 %; Extra seeds 10 %; Seeds per packet 100 seeds. Results: Planting sites 100 sites; Seeds to sow 138 seeds; Whole packets 2 packets.

The example uses the values initially displayed in the fields.

Limitations

Spacing is a simple square grid. Row paths, thinning, seed size, local conditions, and package instructions alter real needs.

Review and reference

Reviewed October 5, 2026. The default example, input boundaries, arithmetic, rounding, and invalid input behavior were checked. The method is explained on How Our Calculators Work; replace example inputs with measurements or current product specifications. This is a planning estimate.

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